Pregnancy, delivery, and neonatal complications among autistic children.

An investigation of the prenatal, delivery, and neonatal experience of 145 autistic children matched with 330 unaffected siblings revealed that among the propositi there was a preponderance of first-born children. Obstetrical records, which had been made prior to the diagnosis of autism, indicated that autistic children were more likely than their siblings to have experienced at least one untoward event during their mothers' gestations and deliveries. Similarly, the autistic children had an increased risk of neonatal complications. Despite the significant excess of total reproductive complications in the autistic series, there was no single event or a combination of biologically related complications that could reasonably account for any large number of cases of autism. While it is possible that autism may be the product of several diverse deleterious events experienced in utero, during delivery, or in the early neonatal period, our finding could be a chance occurrence or could signal the presence of a unknown factor responsible both for autism and for a variety of reproductive complications.